1. Field of the Invention
The present invention relates to an elevator apparatus equipped with elevator traction machine having reduction gear mechanism of parallel axial gears.
2. Description of the Prior Arts
Referring to FIGS. 1 and 2, the conventional elevator traction machine will be illustrated.
In FIGS. 1 and 2, the reference numeral (1) desginates a hatchway; (2) designates a machine room placed above the hatchway; (3) designates a reduction gear unit having parallel axial gears such as helical gears as main parts which is fixed on a floor of the machine room and the reduction gear unit comprises a fixed body (3a) of a gear box; an input shaft (3b) fitted to the fixed body (3a), a middle shaft (3c) fitted to the fixed body (3a) in parallel to the input shaft (3b); an output shaft (3d) fitted to the fixed body (3a) in parallel to the middle shaft (3c); a first gear (3f) of helical gear mounted on the input shaft (3b); a second gear (3g) mounted on the middle shaft (3c) interlocked to the first gear; a third gear (h) of a helical gear mounted on the middle shaft (3c) and a fourth gear (3i) mounted on the output shaft (3d) interlocked to the third gear as the reduction gear mechanism (3e).
The reference numeral (4) designates a traction sheave which is rotatably connected at one end of the output shaft (3d) of the reduction gear unit (3); (5) designates a traction motor connected at one end of the input shaft (3b) of the reduction gear unit (3); (6) designates a main rope suspending a car (7) and a counterweight (8) at the ends of the rope which is wound on the traction sheave (4) and (9) designates a deflector sheave.
In the elevator apparatus having the above-mentioned structure, the traction sheave (4) is turned through the reduction gear unit (3e) by driving the traction motor (5) of the traction machine whereby the car (7) is driven by the main rope (6). The reduction gear unit (3e) is formed by parallel axial gears (3f) to (3i) which impart superior transmission efficiency to the conventional worm gear unit whereby energy can be effectively saved.
However, vibration of the reduction gear unit (3e) shown by the curve b of FIG. 3 is caused in acceleration and deceleration of the car (7) shown by the speed curve a of FIG. 3 by backlash of the parallel axial gears (3f)-(3i) of the reduction gear unit (3e) of the traction machine. The vibration is transmitted through the traction sheave (4) and the main rope (6) to the car (3) whereby a passenger feels uneasy.
When an interlocking gap of gears exists when the weight of the car (7) and the weight of the counterweight (8) are balanced, the vibration of the car (7) increases.